1. Field of the Invention
This invention relates to appliances for preventing airway occlusion during sleep in individuals who suffer from sleep apnea or snoring, or both. More particularly it relates to an appliance that is inserted into a user's oral cavity for providing an air pathway through the oral cavity.
Airway occlusion during sleep may cause cessation of breathing (apnea) and lead to undesirable physiologic changes of hypoxemia and hypercapnia. Persons suffering from sleep apnea are at risk for systemic and pulmonary hypertension, arrhythmias leading to sudden cardiac death, and accidents due to hypersomnolence.
Airway occlusion may be caused by decline in upper airway dilator muscle tone, especially the genioglossus muscle. Redundant pharyngeal tissue and edema may be contributing factors. Sleeping on the back may exacerbate airway occlusion due to the added effect of gravity on the tongue. Sleep apnea is most pronounced during the inspiratory phase of breathing (inhalation). In patients suffering from sleep apnea or snoring, or both, the retroglossal area is usually the most obstructed part of the airway.
2. Related Art
Various devices have been developed to facilitate breathing for those suffering from airway occlusion. One such device, as disclosed in U.S. Pat. No. 4,676,240, issued to Gardy on Jun. 30, 1987, provides a mechanism which holds the tongue forward in a vacuum chamber. Another device is disclosed in U.S. Pat. No. 4,170,230, issued to Nelson on Oct. 9, 1979, which allows the user to breathe through his or her mouth without drying out the mouth. Another device, as disclosed in U.S. Pat. No. 4,198,967, issued to Dror on Apr. 22, 1980, teaches a method of holding the tongue in an unconscious or semi-conscious individual as an adjunct to resuscitation of the individual.
U.S. Pat. No. 3,370,179, issued to Williams on May 1, 1973, discloses a combination resuscitating, aspirating and gastric draining apparatus which includes a tube extended down the throat of a victim in combination with a draining apparatus. This apparatus uses a conventional resuscitating supply source acting through a demand valve and an elongate tube extending down the throat
Appliances are also known which provide for nasal delivery of a positive air supply during both inspiration and exhalation. None of these inventions compensate for redundant pharyngeal tissue and laxity of airway dilator muscle tone or provide a positive air supply via an oral appliance.